Stepped Porous Carbon‐Multilayer Graphene@Fe3C/Fe3N Membrane to Inhibit the Polysulfides Shuttle for High‐Performance Lithium–Sulfur Batteries

摘要

Abstract Lithium–sulfur (Li–S) batteries are regarded as one of the most prominent future‐oriented energy battery systems due to their high theoretical energy density (2600 Wh kg−1). However, the shuttle effect of polysulfides and short cycle life have critically hindered their commercialization. Herein, a stepped porous heterostructured membrane of carbon‐multilayer graphene (MG)@Fe3C/Fe3N is developed by a facile phase inversion method and applied as a current collector to replace Al foil. The special heterostructured membrane with MG can further boost the charge/Li+ ion transfer speed while accommodating the volume expansion in the charge/discharge cycle. The shuttle effect of polysulfides is inhibited by the heterostructure phase of the Fe3C/Fe3N catalytic effect and chemisorption. This synergistic effect is confirmed by density function theory (DFT) calculations. As a result, the C‐MG@Fe3C/Fe3N membranes delivers distinguished discharge capacity and cycling stability of 508.92 mAh g−1 (693.47 mAh g−1) at a large discharge of current of 2 C (at 0.5 C) after 400 cycles (300 cycles) with only 0.36% capacity attenuation per cycle.